In recent years, there is the tendency for sheet-handling apparatuses that the letter (sheet-like article) size that can be handled according to the requirements of mail-handling machines increases, and also the requirements for thickness are increasing year by year from 6 mm, 8 mm to 10 mm and beyond.
Mail-handling machines are equipped with a take-out belt for taking out sheet-like articles, and the sheet-like articles taken out by this take-out belt are separated into individual items by a separation mechanism (mechanism for preventing double take-outs) and then fed downstream.
The separation mechanism may include a vacuum chucking backward-feeding roller that is arranged with a certain gap to the take-out belt, and sheet-like articles are pushed back by being sucked to this backward-feeding roller. The backward-feeding roller is rotatingly driven by a driving mechanism, so that it is arranged at a fixed position.
However, conventionally, the backward-feeding roller is made of a hard material, and the gap between the backward-feeding roller and the take-out belt has a constant size, so that that there is a limit to the thickness of the processed letters that can pass the gap between the take-out belt and the backward-feeding roller.
For this reason, sheet-like articles that are thicker than the gap between the take-out belt and the backward-feeding roller cannot pass the gap and thus cannot be taken out. Moreover, if the gap between the take-out belt and the backward-feeding roller is enlarged, then the problem may arise that the distance too the backward-feeding roller may become too large for thin sheet-like articles, and the functionality of preventing double take-outs may be lost.
While it is conceivable to move the backward-feeding roller and adjust the size of the gap between the backward-feeding roller and the take-out belt in accordance with the thickness of the sheet-like article, in this case, there is the problem that the time needed for this movement is too long as the mass of the backward-feeding roller is quite large, so that the adjustment of the size of the gap cannot be accomplished in time.
Patent Document JP 2007-326713A is an example of related art.